Nihon Dempa Kogyo Co., Ltd.

Hitoshi Sekimoto

Morio Onoe

Masanobu Okazaki

Yukihiro Okamoto

Toshiki Suganuma

Morio Onoue

The outer shape of a quartz crystal blank is processed to have a predetermined shape, thereby providing an SC cut crystal resonator capable of reliably and reproducibly suppressing B mode resonance. In this SC cut crystal resonator, the surface of the quartz crystal orthogonal to the Y axis is rotated through 33&#xb0; to 35&#xb0; about the X axis and is then rotated from this rotated position through 22&#xb0; to 24&#xb0; about the Z axis, and a slender quartz crystal blank oblong in an X' axis direction is cut from the rotated surface. The end surface of the quartz crystal blank orthogonal to the Z&#x2032; axis is tilted in a direction rotated through +7&#xb0; to +13&#xb0; or &#x2212;7&#xb0; to &#x2212;13&#xb0; about the X&#x2032; axis.

SC cut crystal resonator

In a gallium phosphate crystal, a crystallographic Y-axis and a Z-axis that have been rotated about an X-axis counterclockwise through an angle &#x3b1; is referred to as a Y'-axis and a Z&#x2032;-axis, respectively, where the angle &#x3b1; is in a range from 10&#xb0; to 20&#xb0;. A piezoelectric crystal material made of gallium phosphate is provided as a plate-shaped member which is elongate in an X-axis direction and cut from the gallium phosphate crystal parallel to an X-Z&#x2032; crystal plane of the gallium phosphate, and the plate-shaped member has sides parallel to an axis that is obtained by rotating the Y&#x2032;-axis counterclockwise about the X-axis in an angular range from 1&#xb0; to 3&#xb0;.

Piezoelectric crystal material and piezoelectric resonator

At least one pair of exciting electrodes are formed opposite to each other on two major surfaces of a piezoelectric plate. Electrodes and that portion of the piezoelectric plate which is held between at least the exciting electrodes, form a resonance region where thickness-shear vibrations of plural modes are excited. A waveguide path having a cut-off frequency higher than the frequency of at least one desired vibration excited in the resonance region, but lower than the frequencies of the thickness-shear vibrations, whose damping is desired, and excited in the resonance region, is formed and extends in a direction substantially the same as the propagating direction of the thickness-shear vibration whose damping is desired, and has a width 0.5 times or more the width of the resonance region. A vibration absorbent is arranged in the waveguide path.

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Kanagawa, Japan

Hitoshi Sekimoto